Confluent Platform with Apache Flink

This project will set up the following components:

• Confluent Platform 7.5.1

  • broker
  • control-center
  • restproxy
  • connect

• Apache Flink 1.18

  • sql-client
  • jobmanager
  • taskmanager

When the project is running, you'll be able to access the following URLs in your browser:

• Confluent Control Center: http://localhost:9021/
• Apache Flink Dashboard: http://localhost:8081/

And you have access to a number of ReST APIs:

• ReST Proxy http://localhost:8082
• Kafka Connect: http://localhost:8083
• Schema Registry http://localhost:8084
• Broker http://localhost:8090

Getting Started

Build the container instances and start them:

docker-compose build --pull sql-client
docker-compose build --pull jobmanager
docker-compose up

Confirm that the various endpoints are responding:

ReST Proxy:

curl -XGET http://localhost:8082/v3/clusters | jq

Connect:

curl -XGET http://localhost:8083/ | jq

Schema Registry:

curl -XGET http://localhost:8084/config | jq

Broker Metadata:

curl -XGET http://localhost:8090/v1/metadata/id | jq

Generate some data

After the containers have started, we can start by getting data loaded into Kafka; to do this, let's use datagen to create some pageviews:

curl -i -X PUT http://localhost:8083/connectors/datagen_local_01/config \
     -H "Content-Type: application/json" \
     -d '{
            "connector.class": "io.confluent.kafka.connect.datagen.DatagenConnector",
            "key.converter": "org.apache.kafka.connect.storage.StringConverter",
            "kafka.topic": "pageviews",
            "quickstart": "pageviews",
            "max.interval": 1000,
            "iterations": 10000000,
            "tasks.max": "1"
        }'

As soon as that is done, let's run the consumer to inspect the topic:

docker-compose exec broker kafka-console-consumer --topic pageviews --bootstrap-server broker:29092 --from-beginning --max-messages 10

The messages are not looking quite right; let's use the kafka-avro-console-consumer instead:

docker-compose exec connect kafka-avro-console-consumer \
 --bootstrap-server broker:29092 \
 --property schema.registry.url=http://schemaregistry:8084 \
 --topic pageviews \
 --property print.key=true \
 --property key.deserializer=org.apache.kafka.common.serialization.StringDeserializer \
 --property key.separator=" : " \
 --max-messages 10

That works nicely... Let's see how Flink handles Avro:

docker-compose exec sql-client sql-client.sh

To create the pageviews table, you can use this:

CREATE TABLE pageviews (
    viewtime BIGINT,
    userid STRING,
    pageid STRING,
    `ts` TIMESTAMP(3) METADATA FROM 'timestamp',
    `proc_time` AS PROCTIME(),
    WATERMARK FOR `ts` AS `ts` 
) WITH (
    'connector' = 'kafka', 
    'topic' = 'pageviews', 
    'scan.startup.mode' = 'earliest-offset', 
    'properties.bootstrap.servers' = 'broker:29092', 
    'value.format' = 'avro-confluent',
    'value.avro-confluent.schema-registry.url' = 'http://schemaregistry:8084'
);

Now we can create a SELECT statement using the pageviews topic as the source:

SELECT * FROM pageviews;

We get some output! :)

Set up a join

We're going to use user_id for this join

curl -i -X PUT http://localhost:8083/connectors/datagen_users/config \
     -H "Content-Type: application/json" \
     -d '{
            "connector.class": "io.confluent.kafka.connect.datagen.DatagenConnector",
            "kafka.topic": "users",
            "quickstart": "users",
            "key.converter": "org.apache.kafka.connect.storage.StringConverter",
            "max.interval": 1000,
            "iterations": 10000000,
            "tasks.max": "1"
        }'

docker-compose exec sql-client sql-client.sh

CREATE TABLE users (
    registertime BIGINT,
    userid STRING,
    regionid STRING,
    gender STRING,
    `ts` TIMESTAMP(3) METADATA FROM 'timestamp',
    `proc_time` AS PROCTIME(),
    WATERMARK FOR `ts` AS `ts` 
) WITH (
    'connector' = 'kafka', 
    'topic' = 'users', 
    'scan.startup.mode' = 'earliest-offset', 
    'properties.bootstrap.servers' = 'broker:29092', 
    'value.format' = 'avro-confluent',
    'value.avro-confluent.schema-registry.url' = 'http://schemaregistry:8084'
);

You should see:

[INFO] Execute statement succeed.

SELECT * FROM users;

Let's create the stock-trades topic and load some data into it:

curl -i -X PUT http://localhost:8083/connectors/datagen_stock/config \
     -H "Content-Type: application/json" \
     -d '{
            "connector.class": "io.confluent.kafka.connect.datagen.DatagenConnector",
            "kafka.topic": "stock-trades",
            "quickstart": "Stock_Trades",
            "key.converter": "org.apache.kafka.connect.storage.StringConverter",
            "max.interval": 100,
            "iterations": 10000000,
            "tasks.max": "1"
        }'

docker-compose exec sql-client sql-client.sh

CREATE TABLE stock_trades (
    side STRING,
    quantity INT,
    symbol STRING,
    price INT,
    account STRING,
    userid STRING,
    regionid STRING,
    `ts` TIMESTAMP(3) METADATA FROM 'timestamp',
    `proc_time` AS PROCTIME(),
    WATERMARK FOR `ts` AS `ts` 
) WITH (
    'connector' = 'kafka', 
    'topic' = 'stock-trades', 
    'scan.startup.mode' = 'earliest-offset', 
    'properties.bootstrap.servers' = 'broker:29092', 
    'value.format' = 'avro-confluent',
    'value.avro-confluent.schema-registry.url' = 'http://schemaregistry:8084'
);

SELECT * FROM stock_trades;

Let's now attempt a join!

SELECT * FROM stock_trades
  INNER JOIN users
  ON stock_trades.userid = users.userid;

Seems to be working as expected.

---

### Notes below

OR:

docker-compose build --pull sql-client

Start the containers:

docker-compose up

Make sure there are some messages in the user_behavior topic:

docker-compose exec kafka bash -c 'kafka-console-consumer.sh --topic user_behavior --bootstrap-server kafka:9094 --from-beginning --max-messages 10'

If you see messages in the Kafka topic, the next thing to do is to access the topic from within Flink:

docker-compose exec sql-client ./sql-client.sh

You should see:

Reading default environment from: file:/opt/flink/conf/sql-client-conf.yaml

You'll start to see results paging through as a result of the SELECT statement.

docker-compose exec sql-client bash

cd $SQL_CLIENT_HOME/lib
cp flink-sql-connector-kafka-3.0.0-1.17.jar ../../flink/lib/
cd ../../flink/lib/
chown flink:flink flink-sql-connector-kafka-3.0.0-1.17.jar
exit

docker-compose exec broker kafka-console-consumer --topic user_behavior --bootstrap-server broker:29092 --from-beginning --max-messages 10

Now let's connect to the Flink SQL Client:

docker-compose exec sql-client sql-client.sh